test suite: group_mgr initialization fix

test/cmdtest_d/include/group_mgr.py

@@ -108,7 +108,7 @@ class CmdGroupMgr:
 			return [k for k, v in cfgs[str(tmpdir_idx)]['dep_generators'].items()
 						if k in cls.shared_deps and v != cmdname]
 
-		if not hasattr(cls, 'cmd_group'):
+		if not 'cmd_group' in cls.__dict__:
 			cls.cmd_group = self.create_cmd_group(cls, sg_name)
 
 		for a, b in cls.cmd_group: